Underground area in Eridium Blight?

There is a central area blocked by blue light beam, in the middle of the Eridium Blight region. Where do I find the switch to turn the beams off? I have searched and cannot locate anything.---"Old, but still game!" GT: Zanarkand Wolf

Behind the turret, on the opposite side of the wall with the gate that you initially spawn nearest when fast-travelling to the area.---I loved life before internet forums. Back then the only outlet trolls had to spread their trollisms was to talk to their stuffed animals... - DolemiteXP